This invention relates to poultry houses and more particularly to a method and apparatus for controlling a pressure in a poultry house to increase egg production.
The demand for poultry eggs has grown considerably. Poultry eggs are primarily obtained in a large scale manufacturing process that utilizes large buildings known typically as poultry houses. These are generally rectangular in shape and have a plurality of openings used in conjunction with fans or blowers, with various damper arrangements, to provide ventilation.
In U.S. Pat. No. 3,951,336, a typical ventilation system for livestock is described where air is drawn from the building by fans to maintain a slightly less than atmospheric pressure in the building. It is considered important to utilize this slight negative differential pressure to assure an adequate fresh air supply into the building, to preserve the health of the poultry. A certain air turnover rate is desired to avoid build up of moisture or respiration by products as well as to cool or heat the building.
In U.S. Pat. No. 5,336,131, a differential pressure control system for a livestock house is described. This uses a microcomputer based system with various sensors for controlling the air flow through a livestock house, taking into account factors such as outside air temperature, outside air pressure, inside air pressure, etc. The system, while comprehensive, is designed to maintain a programmed negative differential pressure in the building, and is simply directed to more closely controlling the factors which influence the temperature in the building.
While temperature, humidity and the presence of fresh air are known to affect egg production, it has not been known that egg production could be increased by increasing, as opposed to decreasing, the pressure within a poultry house. This aspect of egg production was discovered by the applicant.
Consequently, it is an object of the present invention to provide a method for increasing egg production by using an air pressure control system to obtain a steady air pressure in a poultry house, independent of ambient pressure variations, and preferably to provide a relatively constant positive pressure differential in a poultry house.
It is a further object of the present invention to provide a poultry house having means to provide a relatively constant positive pressure above atmospheric to increase egg production.
It is yet another object to provide a system for providing a stable atmospheric pressure in a poultry house.
These and other objects of the present invention are achieved by a method comprising the steps of providing a poultry house for housing egg laying poultry, providing means for ventilating the poultry house and providing means for controlling the pressure in a poultry house so as to maintain a relatively constant pressure independent of variations in an ambient atmospheric pressure, such that egg production is increased.
It is well known that the ambient atmospheric pressure is quite variable due to weather changes, season changes, and even from morning to night. Most existing ventilation systems generally mirror these atmospheric pressure changes. This variability is believed to be a negative influence on egg production which is resolved by the present invention.
According to the invention, the poultry house for the most part can be of conventional construction except for the ventilation system. In a change from the prior art, fans or blowers are used to blow in fresh air, with exhaust air means being used to restrict the exhaust air discharge in an amount sufficient to achieve a positive building pressure. While positive pressure is not essential, it provides ease in achieving the relatively constant pressure needed to increase egg production. Systems which rely on negative pressure in a poultry house are much more sensitive to ambient pressure changes than a system maintained at a positive pressure. A positive pressure increase can be controlled by controlling fan or blower speed, in combination with fixed discharge openings, with the control used to avoid over-pressurization of the building. On the other hand, fixed blower speeds with control means used to control exhaust air dampers or exhaust air fans may be provided to achieve a balance of adequate ventilation through the building with sufficient resistance so as to achieve a positive internal building pressure, which is more easily maintained relatively constant relative to outside atmospheric pressure changes. In accordance with the invention, adequate ventilation is still accomplished as fresh air is still supplied to the poultry house as exhaust air is removed, the pressure control system designed to assure a degree of positive pressure in the building in combination with the desired house ventilation scheme.
By providing a relatively constant pressure of from about 30.0 to about 31 inches of water, surprisingly it is believed that egg production may be increased from about 1 to about 5%. In a large poultry house, on an annual basis, this can result in a substantial increase in revenue.
As most poultry houses have negative pressure type ventilation systems in place, the invention can be readily incorporated by modification of the existing ventilation system and therefore retrofitting to existing poultry houses is possible, with the cost offset by the increased egg production.
For optimum performance, new poultry houses can be designed to incorporate features which enhance the ability to maintain a relatively constant positive pressure, reducing leakage so as to provide better overall environmental control, as will be discussed in more detail below.